The prior well-known separate dielectric filter is made from a coaxial dielectric resonator, adopting a low pass prototype, and based on a normalized frequency variable from a calculation and an admittance transformation. A capacitor is manufactured on an alumina ceramic substrate, a pin is installed in a hole of the coaxial dielectric resonator and connected with the capacitor, and thus a band-pass dielectric filter is obtained. It has four great shortcomings resulted from the structure of separate dielectric filter: First, the separate dielectric filter adopts an exterior dielectric coupling, which results in a poor reliability, and makes the capacitor and a terminal of the coaxial dielectric resonator easy to fall off. Second, for an increased number of levels, the ceramic-substrated capacitor will have to be lengthened, and is thus very easy to become ruptured during transportation, installation and decline, causing a poor contact. Third, temperature drift of the ceramic substrate as the capacitor substrate at high and low temperatures, due to temperature characteristics of the ceramic substrate, highly tends to result in performance deterioration of the filter. Fourth, since mutual influence of electromagnetic field between all levels of exterior coupling at high frequencies (such as frequencies above 3G) is very strong, it is very difficult to give attention to all levels of coupling, and thus difficult to produce a high-quality filter.